<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:7b0c3c90-e0d6-477b-bb6c-331dcb72a873,g:22724714-30ad-415d-8225-21ef54604f03-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:cdna="http://www.caredxinc.com/20250331" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types1="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2022-03-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.caredxinc.com/20250331">
  <xs:import namespace="http://fasb.org/srt/2024" schemaLocation="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2024" schemaLocation="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2022-03-31" schemaLocation="https://www.xbrl.org/dtr/type/2022-03-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2024" schemaLocation="https://xbrl.sec.gov/country/2024/country-2024.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2024" schemaLocation="https://xbrl.sec.gov/dei/2024/dei-2024.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2024" schemaLocation="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="cdna-20250331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="cdna-20250331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="cdna-20250331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="cdna-20250331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.caredxinc.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheets" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedBalanceSheets">
        <link:definition>9952151 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheetsParenthetical" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>9952152 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofOperations" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedStatementsofOperations">
        <link:definition>9952153 - Statement - Condensed Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofComprehensiveLoss" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedStatementsofComprehensiveLoss">
        <link:definition>9952154 - Statement - Condensed Consolidated Statements of Comprehensive Loss</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofStockholdersEquity" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedStatementsofStockholdersEquity">
        <link:definition>9952155 - Statement - Condensed Consolidated Statements of Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofCashFlows" roleURI="http://www.caredxinc.com/role/CondensedConsolidatedStatementsofCashFlows">
        <link:definition>9952156 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandDescriptionofBusiness" roleURI="http://www.caredxinc.com/role/OrganizationandDescriptionofBusiness">
        <link:definition>9952157 - Disclosure - Organization and Description of Business</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPolicies" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPolicies">
        <link:definition>9952158 - Disclosure - Summary of Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetLossPerShare" roleURI="http://www.caredxinc.com/role/NetLossPerShare">
        <link:definition>9952159 - Disclosure - Net Loss Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurements" roleURI="http://www.caredxinc.com/role/FairValueMeasurements">
        <link:definition>9952160 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CashandMarketableSecurities" roleURI="http://www.caredxinc.com/role/CashandMarketableSecurities">
        <link:definition>9952161 - Disclosure - Cash and Marketable Securities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssets" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssets">
        <link:definition>9952162 - Disclosure - Goodwill and Intangible Assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetComponents" roleURI="http://www.caredxinc.com/role/BalanceSheetComponents">
        <link:definition>9952163 - Disclosure - Balance Sheet Components</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingencies" roleURI="http://www.caredxinc.com/role/CommitmentsandContingencies">
        <link:definition>9952164 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlans" roleURI="http://www.caredxinc.com/role/StockIncentivePlans">
        <link:definition>9952165 - Disclosure - Stock Incentive Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Equity" roleURI="http://www.caredxinc.com/role/Equity">
        <link:definition>9952166 - Disclosure - Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.caredxinc.com/role/IncomeTaxes">
        <link:definition>9952167 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReporting" roleURI="http://www.caredxinc.com/role/SegmentReporting">
        <link:definition>9952168 - Disclosure - Segment Reporting</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPoliciesPolicies" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPoliciesPolicies">
        <link:definition>9955511 - Disclosure - Summary of Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPoliciesTables" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPoliciesTables">
        <link:definition>9955512 - Disclosure - Summary of Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetLossPerShareTables" roleURI="http://www.caredxinc.com/role/NetLossPerShareTables">
        <link:definition>9955513 - Disclosure - Net Loss Per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsTables" roleURI="http://www.caredxinc.com/role/FairValueMeasurementsTables">
        <link:definition>9955514 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CashandMarketableSecuritiesTables" roleURI="http://www.caredxinc.com/role/CashandMarketableSecuritiesTables">
        <link:definition>9955515 - Disclosure - Cash and Marketable Securities (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsTables" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsTables">
        <link:definition>9955516 - Disclosure - Goodwill and Intangible Assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetComponentsTables" roleURI="http://www.caredxinc.com/role/BalanceSheetComponentsTables">
        <link:definition>9955517 - Disclosure - Balance Sheet Components (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesTables" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesTables">
        <link:definition>9955518 - Disclosure - Commitments and Contingencies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansTables" roleURI="http://www.caredxinc.com/role/StockIncentivePlansTables">
        <link:definition>9955519 - Disclosure - Stock Incentive Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingTables" roleURI="http://www.caredxinc.com/role/SegmentReportingTables">
        <link:definition>9955520 - Disclosure - Segment Reporting (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPoliciesSummaryofEffectsofCorrectionofPreviouslyIssuedCondensedConsolidatedFinancialStatementsDetails" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPoliciesSummaryofEffectsofCorrectionofPreviouslyIssuedCondensedConsolidatedFinancialStatementsDetails">
        <link:definition>9955521 - Disclosure - Summary of Significant Accounting Policies - Summary of Effects of Correction of Previously Issued Condensed Consolidated Financial Statements (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails">
        <link:definition>9955522 - Disclosure - Summary of Significant Accounting Policies - Concentration of Credit Risk (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SummaryofSignificantAccountingPoliciesRevenueDetails" roleURI="http://www.caredxinc.com/role/SummaryofSignificantAccountingPoliciesRevenueDetails">
        <link:definition>9955523 - Disclosure - Summary of Significant Accounting Policies - Revenue (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetLossPerShareSummaryofComputationofBasicandDilutedNetLossPerShareDetails" roleURI="http://www.caredxinc.com/role/NetLossPerShareSummaryofComputationofBasicandDilutedNetLossPerShareDetails">
        <link:definition>9955524 - Disclosure - Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetLossPerShareSummaryofPotentiallyDilutiveSecuritiesExcludedfromDilutedNetLossPerShareDetails" roleURI="http://www.caredxinc.com/role/NetLossPerShareSummaryofPotentiallyDilutiveSecuritiesExcludedfromDilutedNetLossPerShareDetails">
        <link:definition>9955525 - Disclosure - Net Loss Per Share - Summary of Potentially Dilutive Securities Excluded from Diluted Net Loss Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsSummaryofFairValueofFinancialAssetsandLiabilitiesMeasuredonRecurringBasisDetails" roleURI="http://www.caredxinc.com/role/FairValueMeasurementsSummaryofFairValueofFinancialAssetsandLiabilitiesMeasuredonRecurringBasisDetails">
        <link:definition>9955526 - Disclosure - Fair Value Measurements - Summary of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsSummaryofIssuancesExercisesChangesinFairValueandReclassificationsofLevel3FinancialInstrumentsDetails" roleURI="http://www.caredxinc.com/role/FairValueMeasurementsSummaryofIssuancesExercisesChangesinFairValueandReclassificationsofLevel3FinancialInstrumentsDetails">
        <link:definition>9955527 - Disclosure - Fair Value Measurements - Summary of Issuances, Exercises, Changes in Fair Value and Reclassifications of Level 3 Financial Instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsAdditionalInformationDetails" roleURI="http://www.caredxinc.com/role/FairValueMeasurementsAdditionalInformationDetails">
        <link:definition>9955528 - Disclosure - Fair Value Measurements - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CashandMarketableSecuritiesSummaryofReconciliationofCashandCashEquivalentsDetails" roleURI="http://www.caredxinc.com/role/CashandMarketableSecuritiesSummaryofReconciliationofCashandCashEquivalentsDetails">
        <link:definition>9955529 - Disclosure - Cash and Marketable Securities - Summary of Reconciliation of Cash and Cash Equivalents (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CashandMarketableSecuritiesSummaryofComponentsofMarketableSecuritiesDetails" roleURI="http://www.caredxinc.com/role/CashandMarketableSecuritiesSummaryofComponentsofMarketableSecuritiesDetails">
        <link:definition>9955530 - Disclosure - Cash and Marketable Securities - Summary of Components of Marketable Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsAdditionalInformationDetails" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsAdditionalInformationDetails">
        <link:definition>9955531 - Disclosure - Goodwill and Intangible Assets - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsSummaryofIntangibleAssetsDetails" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsSummaryofIntangibleAssetsDetails">
        <link:definition>9955532 - Disclosure - Goodwill and Intangible Assets - Summary of Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsSummaryofIntangibleAssetsDetails_1" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsSummaryofIntangibleAssetsDetails_1">
        <link:definition>9955532 - Disclosure - Goodwill and Intangible Assets - Summary of Intangible Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsSummaryofFiniteLivedIntangibleAssetsAmortizationExpenseDetails" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsSummaryofFiniteLivedIntangibleAssetsAmortizationExpenseDetails">
        <link:definition>9955533 - Disclosure - Goodwill and Intangible Assets - Summary of Finite-Lived Intangible Assets Amortization Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandIntangibleAssetsSummaryofEstimatedFutureAmortizationExpenseofIntangibleAssetswithFiniteLivesDetails" roleURI="http://www.caredxinc.com/role/GoodwillandIntangibleAssetsSummaryofEstimatedFutureAmortizationExpenseofIntangibleAssetswithFiniteLivesDetails">
        <link:definition>9955534 - Disclosure - Goodwill and Intangible Assets - Summary of Estimated Future Amortization Expense of Intangible Assets with Finite Lives (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetComponentsSummaryofInventoryDetails" roleURI="http://www.caredxinc.com/role/BalanceSheetComponentsSummaryofInventoryDetails">
        <link:definition>9955535 - Disclosure - Balance Sheet Components - Summary of Inventory (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetComponentsSummaryComponentsofAccruedExpensesandOtherCurrentLiabilitiesDetails" roleURI="http://www.caredxinc.com/role/BalanceSheetComponentsSummaryComponentsofAccruedExpensesandOtherCurrentLiabilitiesDetails">
        <link:definition>9955536 - Disclosure - Balance Sheet Components - Summary Components of Accrued Expenses and Other Current Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesAdditionalInformationDetails" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesAdditionalInformationDetails">
        <link:definition>9955537 - Disclosure - Commitments and Contingencies - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesSummaryofLeaseCostDetails" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesSummaryofLeaseCostDetails">
        <link:definition>9955538 - Disclosure - Commitments and Contingencies - Summary of Lease Cost (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesSummaryofOtherInformationRelatedtoLeaseDetails" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesSummaryofOtherInformationRelatedtoLeaseDetails">
        <link:definition>9955539 - Disclosure - Commitments and Contingencies - Summary of Other Information Related to Lease (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesScheduleofFutureMinimumLeaseCommitmentsunderOperatingandFinanceLeasesDetails" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesScheduleofFutureMinimumLeaseCommitmentsunderOperatingandFinanceLeasesDetails">
        <link:definition>9955540 - Disclosure - Commitments and Contingencies - Schedule of Future Minimum Lease Commitments under Operating and Finance Leases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesScheduleofFutureMinimumLeaseCommitmentsunderOperatingandFinanceLeasesDetails_1" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesScheduleofFutureMinimumLeaseCommitmentsunderOperatingandFinanceLeasesDetails_1">
        <link:definition>9955540 - Disclosure - Commitments and Contingencies - Schedule of Future Minimum Lease Commitments under Operating and Finance Leases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandContingenciesSummarizestheNoncashInformationDetails" roleURI="http://www.caredxinc.com/role/CommitmentsandContingenciesSummarizestheNoncashInformationDetails">
        <link:definition>9955541 - Disclosure - Commitments and Contingencies - Summarizes the Noncash Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansSummaryofOptionUnvestedRSUActivityunder2014EquityIncentivePlanand2016InducementEquityIncentivePlanandRelatedInformationDetails" roleURI="http://www.caredxinc.com/role/StockIncentivePlansSummaryofOptionUnvestedRSUActivityunder2014EquityIncentivePlanand2016InducementEquityIncentivePlanandRelatedInformationDetails">
        <link:definition>9955542 - Disclosure - Stock Incentive Plans - Summary of Option, Unvested RSU Activity under 2014 Equity Incentive Plan and 2016 Inducement Equity Incentive Plan and Related Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansAdditionalInformationDetails" roleURI="http://www.caredxinc.com/role/StockIncentivePlansAdditionalInformationDetails">
        <link:definition>9955543 - Disclosure - Stock Incentive Plans - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansSummaryofOptionsOutstandingVestedandExpectedtoVestDetails" roleURI="http://www.caredxinc.com/role/StockIncentivePlansSummaryofOptionsOutstandingVestedandExpectedtoVestDetails">
        <link:definition>9955544 - Disclosure - Stock Incentive Plans - Summary of Options Outstanding Vested and Expected to Vest (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansSummaryofWeightedAverageAssumptionsUsedtoEstimatedFairValuesofShareBasedAwardsDetails" roleURI="http://www.caredxinc.com/role/StockIncentivePlansSummaryofWeightedAverageAssumptionsUsedtoEstimatedFairValuesofShareBasedAwardsDetails">
        <link:definition>9955545 - Disclosure - Stock Incentive Plans - Summary of Weighted-Average Assumptions Used to Estimated Fair Values of Share-Based Awards (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockIncentivePlansSummaryofExpenseRelatingtoEmployeeandNonemployeeStockBasedPaymentAwardsfromStockOptionsandRSUsDetails" roleURI="http://www.caredxinc.com/role/StockIncentivePlansSummaryofExpenseRelatingtoEmployeeandNonemployeeStockBasedPaymentAwardsfromStockOptionsandRSUsDetails">
        <link:definition>9955546 - Disclosure - Stock Incentive Plans - Summary of Expense Relating to Employee and Nonemployee Stock-Based Payment Awards from Stock Options and RSUs (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EquityDetails" roleURI="http://www.caredxinc.com/role/EquityDetails">
        <link:definition>9955547 - Disclosure - Equity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.caredxinc.com/role/IncomeTaxesDetails">
        <link:definition>9955548 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingNarrativeDetails" roleURI="http://www.caredxinc.com/role/SegmentReportingNarrativeDetails">
        <link:definition>9955549 - Disclosure - Segment Reporting - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingSummaryofReportableRevenuesbyGeographicRegionsDetails" roleURI="http://www.caredxinc.com/role/SegmentReportingSummaryofReportableRevenuesbyGeographicRegionsDetails">
        <link:definition>9955550 - Disclosure - Segment Reporting - Summary of Reportable Revenues by Geographic Regions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingSummaryofLongLivedAssetsConsistingofPropertyandEquipmentNetbyGeographicRegionsDetails" roleURI="http://www.caredxinc.com/role/SegmentReportingSummaryofLongLivedAssetsConsistingofPropertyandEquipmentNetbyGeographicRegionsDetails">
        <link:definition>9955551 - Disclosure - Segment Reporting - Summary of Long-Lived Assets Consisting of Property and Equipment, Net by Geographic Regions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentReportingReconciliationofRevenuetoNetProfitLossDetails" roleURI="http://www.caredxinc.com/role/SegmentReportingReconciliationofRevenuetoNetProfitLossDetails">
        <link:definition>9955552 - Disclosure - Segment Reporting - Reconciliation of Revenue to Net Profit (Loss) (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="cdna_PatientAndDigitalSolutionsMember" abstract="true" name="PatientAndDigitalSolutionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_IncreaseDecreaseInOperatingLeaseLiabilities" abstract="false" name="IncreaseDecreaseInOperatingLeaseLiabilities" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_PaymentsToAcquireCapitalExpendituresNet" abstract="false" name="PaymentsToAcquireCapitalExpendituresNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_ScheduleOfIntangibleAssetsTableTableTextBlock" abstract="false" name="ScheduleOfIntangibleAssetsTableTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="cdna_ScheduleOfFinanceLeaseAndOperatingLeaseLiabilityMaturityTableTextBlock" abstract="false" name="ScheduleOfFinanceLeaseAndOperatingLeaseLiabilityMaturityTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="cdna_ScheduleOfShareBasedCompensationStockOptionsAndUnvestedRestrictedStockUnitsActivityTableTableTextBlock" abstract="false" name="ScheduleOfShareBasedCompensationStockOptionsAndUnvestedRestrictedStockUnitsActivityTableTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="cdna_MedicareMember" abstract="true" name="MedicareMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_EarningsPerShareBasicAndDilutedOtherDisclosureAbstract" abstract="true" name="EarningsPerShareBasicAndDilutedOtherDisclosureAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_EarningPerShareBasicAndDilutedAbstract" abstract="true" name="EarningPerShareBasicAndDilutedAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_EmployeeAndNonEmployeeStockOptionsMember" abstract="true" name="EmployeeAndNonEmployeeStockOptionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_BusinessAcquisitionContingentConsiderationMember" abstract="true" name="BusinessAcquisitionContingentConsiderationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_AssetAcquisitionContingentConsiderationMember" abstract="true" name="AssetAcquisitionContingentConsiderationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cdna_BusinessCombinationContingentConsiderationLiabilityMeasurementInputDiscountRate" abstract="false" name="BusinessCombinationContingentConsiderationLiabilityMeasurementInputDiscountRate" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="cdna_ShortTermMarketableSecuritiesAbstract" abstract="true" name="ShortTermMarketableSecuritiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_MarketableSecuritiesAmortizedCostShortTerm" abstract="false" name="MarketableSecuritiesAmortizedCostShortTerm" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_MarketableSecuritiesAccumulatedUnrecognizedHoldingGainLossShortTerm" abstract="false" name="MarketableSecuritiesAccumulatedUnrecognizedHoldingGainLossShortTerm" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_MarketableSecuritiesFairValueShortTerm" abstract="false" name="MarketableSecuritiesFairValueShortTerm" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_ScheduleOfFiniteAndInfiniteLivedIntangibleAssetsTable" abstract="true" name="ScheduleOfFiniteAndInfiniteLivedIntangibleAssetsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="cdna_AcquiredAndDevelopedTechnologyMember" abstract="true" name="AcquiredAndDevelopedTechnologyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_CommercializationRightsMember" abstract="true" name="CommercializationRightsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_AcquiredInProcessTechnologyMember" abstract="true" name="AcquiredInProcessTechnologyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_ScheduleOfFiniteAndInfiniteLivedIntangibleAssetsLineItems" abstract="true" name="ScheduleOfFiniteAndInfiniteLivedIntangibleAssetsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_FiniteLivedIntangibleForeignCurrencyTranslation" abstract="false" name="FiniteLivedIntangibleForeignCurrencyTranslation" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_CostOfTestingMember" abstract="true" name="CostOfTestingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_CostOfProductMember" abstract="true" name="CostOfProductMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_CostOfPatientAndDigitalSolutionsMember" abstract="true" name="CostOfPatientAndDigitalSolutionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_AccruedClinicalAndCostOfOtherStudiesCurrent" abstract="false" name="AccruedClinicalAndCostOfOtherStudiesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_AccruedSampleProcessingFees" abstract="false" name="AccruedSampleProcessingFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_AccruedTravelAndExpenses" abstract="false" name="AccruedTravelAndExpenses" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_AccruedShippingExpenses" abstract="false" name="AccruedShippingExpenses" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_DeferredPaymentsForIntangibleAssets" abstract="false" name="DeferredPaymentsForIntangibleAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_AccruedLicenseAndOtherCollaborationFees" abstract="false" name="AccruedLicenseAndOtherCollaborationFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_AccruedCapitalExpenditures" abstract="false" name="AccruedCapitalExpenditures" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_CAREDXINCVsNateraIncMember" abstract="true" name="CAREDXINCVsNateraIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_SecuritiesClassActionMember" abstract="true" name="SecuritiesClassActionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cdna_CompensatoryDamagesMember" abstract="true" name="CompensatoryDamagesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_PunitiveDamagesMember" abstract="true" name="PunitiveDamagesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_IBoxLicenseAndCollaborationAgreementMember" abstract="true" name="IBoxLicenseAndCollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cdna_LesseeOperatingLeaseSubleaseTermArrangement" abstract="false" name="LesseeOperatingLeaseSubleaseTermArrangement" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_LesseeOperatingLeaseSubleaseBaseRent" abstract="false" name="LesseeOperatingLeaseSubleaseBaseRent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_LicenseAndCollaborationAgreementLicensePeriod" abstract="false" name="LicenseAndCollaborationAgreementLicensePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_LossContingencyNumberOfAdvertisements" abstract="false" name="LossContingencyNumberOfAdvertisements" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="cdna_LossContingencyTrialDuration" abstract="false" name="LossContingencyTrialDuration" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_LeaseOtherInformationAbstract" abstract="true" name="LeaseOtherInformationAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" abstract="false" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsAvailableForGrantRollForward" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsAvailableForGrantRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardCommonStockAwardsForServices" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardCommonStockAwardsForServices" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsNumberOfSharesOutstandingRollForward" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsNumberOfSharesOutstandingRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsNumberOfRSUSharesRollForward" abstract="true" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsNumberOfRSUSharesRollForward" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="cdna_TwoThousandAndFourteenEmployeeStockPurchasePlanMember" abstract="true" name="TwoThousandAndFourteenEmployeeStockPurchasePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAmountOfOutstandingStockMaximum" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAmountOfOutstandingStockMaximum" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfferingPeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOfferingPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingNumber" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingNumber" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingNumber" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedWeightedAverageExercisePrice" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedWeightedAverageExercisePrice" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingWeightedAverageRemainingContractualTerm" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingAggregateIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedOutstandingAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingAggregateIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestOutstandingAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="cdna_RestOfTheWorldMember" abstract="true" name="RestOfTheWorldMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="cdna_ReportableSegmentMember" abstract="true" name="ReportableSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="cdna_ResearchMaterialsAndClinicalTrialsExpense" abstract="false" name="ResearchMaterialsAndClinicalTrialsExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
